Mobile communication system, mobile station apparatus, base station apparatus and random access channel transmitting method

ABSTRACT

To improve the delivery probability of a random access channel and increase the information amount notified on the random access channel. In a mobile communication system in which a mobile station apparatus and base station apparatus perform multicarrier communication with each other, the mobile station apparatus sets transmission control information about a random access channel based on a state of the mobile station apparatus in transmitting the random access channel, and the base station apparatus determines the state of the mobile station apparatus based on the transmission control information notified on the random access channel, and performs optimal scheduling corresponding to the state of the mobile station apparatus.

This application is a reissue of U.S. Pat. No. 8,503,413 issued on Aug.6, 2013. The present application also claims priority benefits ofPCT/JP2007/066093, filed Aug. 20, 2007, and Japanese Patent ApplicationNo. 2006-232464, filed on Aug. 29, 2006. The entirety of each of theabove-identified documents is hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a mobile communication system, mobilestation apparatus, base station apparatus and random access channeltransmitting method using a cellular wireless system.

BACKGROUND ART

Currently, as RAT that is Radio Access Technology, W-CDMA (Wideband-CodeDivision Multiple Access) specified in 3GPP (3rd Generation PartnershipProject) is standardized as the 3rd generation cellular mobilecommunication system, and its services have been started sequentially(for example, see Non-patent Document 1).

Further, evolution has been studied in 3rd Generation RAT (EvolvedUniversal Terrestrial Radio Access, hereinafter referred to as “EUTRA”)and 3rd Generation RAT access network (Evolved Universal TerrestrialRadio Access Network, hereinafter referred to as “EUTRAN”). In EUTRA, asa communication system, an OFDMA (Orthogonal Frequency DivisionMultiplexing Access) system has been proposed (for example, seeNon-patent Document 2).

In cellular mobile communication system, a mobile station, which is notassigned radio resources for a reason such as a state immediately afterturn-on and the like, performs uplink transmission to a base stationusing the Random Access Channel (hereinafter, referred to as “RACH” asappropriate). Since the RACH is transmitted using radio resources thatcan be shared by mobile stations, it is considered that the RACHcollides with another mobile station depending on the transmissiontiming. Therefore, mutually orthogonal data sequences are prepared, theorthogonal data sequence is transmitted on the RACH, and the basestation is thereby capable of dividing received signals even with thesame transmission timing when the signals are different data signalsequences. Such an orthogonal data sequence is called the signature, anda signal formed of the signature is called the RACH Preamble, and isused by a base station to identify a mobile station.

However, a collision occurs in the case that a plurality of mobilestation selects the same RACH preamble at the same transmission timing,and in this case, retransmission processing is performed.

Uplink random access procedures in the W-CDMA system will be describedbriefly with reference to FIG. 17. FIG. 17 is a flowchart to explaintransmission procedures of uplink random access channel in the W-CDMAsystem.

As shown in FIG. 17, a mobile station first calculates initialtransmission power of the RACH preamble (step (hereafter, abbreviated as“ST”) 11). The initial transmission power is calculated in the mobilestation from a measurement result of an intercell interference amount,downlink common pilot channel or the like. Next, the mobile stationselects transmission timing of the RACH preamble (ST12), andsubsequently, randomly selects one from among a plurality of signaturesto generate the RACH preamble (ST13). Then, the mobile station transmitsthe RACH preamble with the initial transmission power at thetransmission timing to a base station (ST14).

After transmitting the RACH preamble, the mobile station determineswhether ACK (Acknowledge) indicative of transmission permission isreturned from the base station (ST 15). Herein, when ACK is returned,the mobile station starts actual data transmission called the RACHmessage (ST 16). Meanwhile, when ACK is not returned from the basestation, or NACK (Not Acknowledge) is returned, the mobile stationchecks whether or not the number of retransmissions beforehand definedexpires (ST 17). When the number of retransmissions does not expire, themobile station increases the transmission power (ST 18), newly selectstransmission timing for retransmission, and generates the RACH preamblefrom a randomly selected signature to retransmit (ST 12, ST 13). In thecase where the mobile station checks whether or not the number ofretransmissions beforehand defined expires at ST 17, while repeating thesame processing, and cannot receive ACK from the base retransmissionsexpires, the mobile station judges as RACH transmission failure (ST 19),and finishes a series of procedures.

In addition, due to differences in wireless system, EUTRA requirescontrol different from the above-mentioned random access procedures inthe W-CDMA system. FIG. 18 is a diagram showing an example of channelmapping of RACH proposed in EUTRA. In this example, the RACH uses aregion of 1.25 MHz within system frequency bandwidth BW, and further,uses a one-subframe interval TTI (Transmission Timing Interval) in thetime domain. In addition, since the RACH is used in a stage that uplinksynchronization has not been acquired, guard time is required prior andsubsequent to actual RACH transmission for the purpose of preventinginterference of transmission data due to propagation delay.

In EUTRA, it is studied that the random access channel is used for thepurposes of a mobile station registering the position, notifyinghandover to a base station that is a handover destination, requestingradio resources, transmitting data in intermittent transmission,maintaining uplink radio synchronization, and the like.

In EUTRA, due to the relationship of the TTI length of the RACH andtransmission bandwidth, it is anticipated that the number of data bitsthat can be contained in the RACH is lower than that in the W-CDMAsystem. Therefore, a method is required for implicitly notifyinginformation without using data that is actually transmitted. Non-patentDocument 3 proposes a method of notifying information using a number ofa signature that is a data sequence included in the RACH preamble.Herein, this method is explained with reference to FIG. 19.

FIG. 19 shows an example in which there are 32 data sequences usable asthe RACH preamble, and numbers of signatures to use are classifiedaccording to a reason of RACH transmission and quality informationindicator (Channel Quality Indicator (hereinafter, referred to as“CQI”)) at the transmission. For example, when the RACH is transmittedat initial transmission, and the CQI of the mobile station at thetransmission is classified as “High”, the mobile station selects onefrom among signature numbers 3 to 5 as shown in FIG. 19, and transmitsthe RACH preamble. By using this method, without being included inactual transmission data, the base station is capable of grasping thereason of RACH transmission and CQI of the mobile station from thereceived signature number.

Further, in EUTRA, technique called interference coordination isproposed to reduce an uplink intercell interference amount (for example,see Non-patent Document 2). A plurality of methods is proposed as theinterference coordination, and as a predominant method, such a method isproposed that the frequency domain usable in the system is divided intosome regions, mobile stations are divided into a plurality of groupsbased on the transmission power, downlink reception quality (path-loss,or CQI) and the like, each group is associated with the dividedfrequency region, and that the mobile stations perform transmission onlyin the associated frequency regions (for example, see Non-patentDocument 4). Non-patent Document 4 introduces a method of setting highertarget quality of base-station received power in the associatedfrequency region as the mobile station comes closer to the base station,and thereby improving throughput of transmission data without increasingthe uplink intercell interference amount. Herein, this method isexplained with reference to FIGS. 20 and 21.

FIG. 20 is a diagram showing that mobile stations UE_A and UE_B arelocated in cells A to C. Herein, it is assumed that UE_A and UE_Bcommunicate with the cell A. At this point, since UE_A is located nearthe center (base station) of the cell A, it is considered that downlinkreception quality of UE_A is good, and that at the same time, the uplinkintercell interference amount hardly exists to peripheral cells (cell Band cell C). Meanwhile, since UE_B is located in the cell edge of thecell A, it is considered that the downlink reception quality is poor,and that at the same time, the uplink intercell interference amount islarge to the peripheral cells (cell B and cell C). Therefore, UE_B needsto set the target quality low to reduce the uplink intercellinterference amount to the peripheral cells. Meanwhile, UE_A providesfew uplink intercell interference amount to the peripheral cells, and isbetter to set the target quality high to improve uplink throughput.

FIG. 21 is a diagram showing an example for setting different targetquality for each frequency region. In FIG. 21, the frequency range ofthe system is divided into four regions of from RU_BW1 to RU_BW4.Further, mobile stations in the cell are grouped to four stagesaccording to the reception quality, and are assigned the regionsstarting with RU_BW1 for an excellent quality group. In other words,mobile stations belonging to the poorest quality group use RU_BW4. Thetarget quality of mobile stations belonging to RU_BW4 is Target A, andthe target quality is set higher by STEP_n that is a predetermined stepwidth as the quality of the group increases. By this method, it ispossible to improve uplink throughput without increasing the uplinkintercell interference amount to peripheral cells.

In addition, as the target quality, assumed is SIR(Signal-to-Interference Ratio), SINR (Signal-to-Interference plus NoiseRation), SNR (Signal-to-Noise Ratio), path-loss or the like.

Non-patent Document 1: Keiji Tachikawa, “W-CDMA mobile communicationsystem”, ISBN4-621-04894-5, Initial print on Jun. 25, 2001, Maruzen Co.,Ltd

Non-patent Document 2: 3GPP TR(Technical Report) 25.814, V1.5.0(2006-5), Physical Layer Aspects for Evolved UTRA.http://www.3gpp.org/ftp/Specs/html-info/25814.htm

Non-patent Document 3: NTT DoCoMo. et al, “Random Access ChannelStructure for E-UTRA Uplink”, 3GPP TSG RAN WG1 Meeting #45, Shanghai,China, 8-12 May, 2006, R1-061184

Non-patent Document 4: Nokia, “Uplink inter cell interference mitigationand text proposal”, 3GPP TSG RAN WG1 Meeting #44, Denver, USA, 13-17Feb., 2006, R1-060298

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

However, in the method of implicitly notifying information with asignature number as shown in FIG. 19, when the reason of RACHtransmission is the same and there is a plurality of mobile stationshaving almost the same reception quality state, since the number ofselectable signatures is limited more s ignificantly than normal, thereis the problem that the collision probability of RACH preambles is high.

Meanwhile, in the interference coordination method as shown in FIG. 21,since any consideration is not given to RACH transmission, mobilestations transmit the RACH with initial transmission power correspondingto the reception quality in any frequency regions at the time of RACHtransmission. As a result, even a mobile station near the cell centercannot transmit the RACH with high transmission power, and there is theproblem that the delivery probability cannot be improved.

The present invention was carried out in view of such problems, and itis an object of the invention to provide a mobile communication system,mobile station apparatus, base station apparatus and random accesschannel transmitting method for improving the delivery probability of arandom access channel without increasing the uplink intercellinterference amount, while increasing the information amount notified onthe random access channel.

Means for Solving the Problem

(1) To attain the above-mentioned object, the present invention tookmeasures as described below. In other words, a mobile communicationsystem according to the invention is a mobile communication system inwhich a mobile station apparatus and base station apparatus performcommunication with each other, and is characterized in that the mobilestation apparatus sets transmission control information about a randomaccess channel based on a state of the mobile station apparatus at thetime of transmitting the random access channel, and that the basestation apparatus determines the state of the mobile station apparatusbased on the transmission control information notified on the randomaccess channel, and performs scheduling corresponding to the state ofthe mobile station apparatus.

Thus, the mobile station apparatus sets transmission control informationof a random access channel based on a state of the mobile stationapparatus, while the base station apparatus performs schedulingcorresponding to the state of the mobile station apparatus based on thetransmission control information. According to this means, by settingthe transmission control information of the random access channel basedon, for example, as a state of the mobile station, quality informationindicator at the time the random access channel is transmitted, whilefurther setting, as the transmission control information of the randomaccess channel, transmission power for not increasing interference toperipheral cells, it is possible to enhance the reception quality of therandom access channel in the base station apparatus, and therefore, itis possible to improve the delivery probability of the random accesschannel without increasing the uplink intercell interference amount.Further, for example, by implicitly notifying the quality informationindicator using the transmission frequency region of the random accesschannel, it is possible to increase the information amount notified onthe random access channel.

(2) Further, in the mobile communication system according to theinvention, the mobile station apparatus is characterized by setting thetransmission control information based on at least one information of ameasured quality information indicator and a transmission reason of therandom access channel as the state of the mobile station apparatus.

Thus, the mobile station apparatus sets the transmission controlinformation based on at least one information of a measured qualityinformation indicator and a transmission reason of the random accesschannel, and is thereby capable of setting the transmission controlinformation in response to the state of the mobile station apparatus intransmitting the random access channel.

(3) Furthermore, in the mobile communication system of the invention,the mobile station apparatus is characterized by setting one of atransmission frequency region, transmission power and a signature of therandom access channel or a combination thereof as the transmissioncontrol information.

Thus, as the transmission control information, the mobile stationapparatus sets one of a transmission frequency region, transmissionpower and a signature of the random access channel or a combinationthereof, and it is thereby possible to make the base station apparatusgrasp various states of the mobile station apparatus using one of thetransmission frequency region, transmission power and the signature ofthe random access channel or a combination thereof.

(4) Still furthermore, in the mobile communication system of theinvention, it is a feature that the transmission frequency region isobtained by dividing a transmission bandwidth of the base stationapparatus into a plurality of regions corresponding to the receptionquality of the mobile station apparatus, and that different transmissionpower is set for each transmission frequency region.

Thus, since the transmission bandwidth of the base station apparatus isdivided into a plurality of regions corresponding to the receptionquality of the mobile station apparatus, and different transmissionpower is set for each transmission frequency region, it is possible toenhance the reception quality of the random access channel in the basestation apparatus. By this means, it is possible to enhance the deliveryprobability of the random access channel without increasing the uplinkintercell interference amount.

(5) Further, in the mobile communication system of the invention, themobile station apparatus is characterized by setting, as thetransmission control information, the transmission frequency regioncorresponding to the quality information indicator and the transmissionpower corresponding to the transmission frequency region, andtransmitting the random access channel using the transmission controlinformation.

Thus, the mobile station apparatus sets the transmission frequencyregion corresponding to the quality information indicator and thetransmission power corresponding to the transmission frequency region asthe transmission control information, and transmits the random accesschannel using the transmission control information, and it is therebypossible to enhance the reception quality of the random access channelin the base station apparatus. By this means, it is possible to improvethe delivery probability of the random access channel without increasingthe uplink intercell interference amount.

Further, the mobile station apparatus sets the transmission frequencyregion corresponding to the quality information indicator, and isthereby capable of implicitly notifying the base station apparatus ofthe quality information indicator in transmitting the random accesschannel through the transmission frequency region, and therefore, it ispossible to increase the information amount notified on the randomaccess channel.

(6) Furthermore, in the mobile communication system of the invention,the mobile station apparatus is characterized by setting, as thetransmission control information, the transmission frequency regioncorresponding to a combination of the quality information indicator anda transmission reason, and the transmission power corresponding to thetransmission frequency region, and transmitting the random accesschannel using the transmission control information.

Thus, since the mobile station apparatus sets, as the transmissioncontrol information, the transmission frequency region corresponding toa combination of the quality information indicator and transmissionreason, and the transmission power corresponding to the transmissionfrequency region, and transmits the random access channel using thetransmission control information, it is possible to enhance thereception quality of the random access channel in the base stationapparatus. By this means, it is possible to improve the deliveryprobability of the random access channel without increasing the uplinkintercell interference amount.

Further, the mobile station apparatus sets the transmission frequencyregion corresponding to a combination of the quality informationindicator and transmission reason, and is thereby capable of implicitlynotifying the base station apparatus of the quality informationindicator in transmitting the random access channel and the transmissionreason of the random access channel through the transmission frequencyregion, and therefore, it is possible to increase the information amountnotified on the random access channel.

(7) Moreover, in the mobile communication system of the invention, themobile station apparatus is characterized by setting, as thetransmission control information, the transmission frequency regioncorresponding to the quality information indicator, the transmissionpower corresponding to the transmission frequency region, and thesignature corresponding to the transmission reason, and transmitting therandom access channel using the transmission control information.

Thus, the mobile station apparatus sets, as the transmission controlinformation, the transmission frequency region corresponding to thequality information indicator, the transmission power corresponding tothe transmission frequency region, and the signature corresponding tothe transmission reason, and transmits the random access channel usingthe transmission control information, and it is thereby possible toenhance the reception quality of the random access channel in the basestation apparatus. By this means, it is possible to improve the deliveryprobability of the random access channel without increasing the uplinkintercell interference amount.

Further, the mobile station apparatus sets the transmission frequencyregion corresponding to the quality information indicator, while furthersetting the signature corresponding to the transmission reason, and isthereby capable of implicitly notifying the base station apparatus ofthe quality information indicator in transmitting the random accesschannel through the transmission frequency region, and implicitlynotifying the base station apparatus of the transmission reason of therandom access channel through the signature, and therefore, it ispossible to increase the information amount notified on the randomaccess channel.

(8) Further, in the mobile communication system, the mobile stationapparatus is characterized by sequentially repeating retransmissionprocedures in the transmission frequency region corresponding to thequality information indicator lower than a measurement value, inretransmitting the random access channel.

Thus, in retransmitting the random access channel, since retransmissionprocedures are sequentially repeated in the transmission frequencyregion corresponding to the quality information indicator lower than ameasurement value, even when the random access channel cannot betransmitted with the measurement value, it is possible to vary thetransmission frequency region as appropriate, and to retransmit therandom access channel in an environment for more facilitatingtransmission.

(9) Furthermore, in the mobile communication system of the invention,the mobile station apparatus is characterized by setting, as thetransmission control information, the signature corresponding to thequality information indicator, the transmission frequency regioncorresponding to the transmission reason, and the transmission powercorresponding to the transmission frequency region, and transmitting therandom access channel using the transmission control information.

Thus, the mobile station apparatus sets, as the transmission controlinformation, the signature corresponding to the quality informationindicator, the transmission frequency region corresponding to thetransmission reason, and the transmission power corresponding to thetransmission frequency region, and transmits the random access channelusing the transmission control information, and it is thereby possibleto enhance the reception quality of the random access channel in thebase station apparatus. By this means, it is possible to improve thedelivery probability of the random access channel without increasing theuplink intercell interference amount.

Further, the mobile station apparatus sets the signature correspondingto the quality information indicator, while further setting thetransmission frequency region corresponding to the transmission reason,and is thereby capable of implicitly notifying the base stationapparatus of the quality information indicator in transmitting therandom access channel through the signature, and implicitly notifyingthe base station apparatus of the transmission reason of the randomaccess channel through the transmission frequency region, and therefore,it is possible to increase the information amount notified on the randomaccess channel.

(10) Moreover, in the mobile communication system of the invention, themobile station apparatus is characterized by setting, as thetransmission control information, the transmission frequency regioncorresponding to the transmission reason and the transmission powercorresponding to the transmission frequency region, and transmitting therandom access channel using the transmission control information.

Thus, the mobile station apparatus sets the transmission frequencyregion corresponding to the transmission reason and the transmissionpower corresponding to the transmission frequency region as thetransmission control information, and transmits the random accesschannel using the transmission control information, and it is therebypossible to enhance the reception quality of the random access channelin the base station apparatus. By this means, it is possible to improvethe delivery probability of the random access channel without increasingthe uplink intercell interference amount.

Further, the mobile station apparatus sets the transmission frequencyregion corresponding to the transmission reason, and is thereby capableof implicitly notifying the base station apparatus of the transmissionreason of the random access channel through the transmission frequencyregion, and therefore, it is possible to increase the information amountnotified on the random access channel.

(11) Further, in the mobile communication system of the invention, it isa feature that the transmission frequency region is obtained by dividinga transmission bandwidth of the base station apparatus into a pluralityof regions corresponding to the reception quality of the mobile stationapparatus, and that different transmission power is set for eachtransmission frequency region.

Thus, since different transmission power is set for each transmissionfrequency region, by selecting a transmission frequency region as thetransmission control information, and setting corresponding transmissionpower in the frequency region, it is possible to implicitly notifyingthe base station apparatus of the quality information indicator intransmitting the random access channel, for example.

(12) Furthermore, in the mobile communication system of the invention,the mobile station apparatus is characterized by setting, as thetransmission control information, the transmission power correspondingto the quality information indicator, and transmitting the random accesschannel using the transmission control information.

Thus, the mobile station apparatus sets the transmission powercorresponding to the quality information indicator, transmits the randomaccess channel using the transmission control information, and isthereby capable of implicitly notifying the base station apparatus ofthe quality information indicator in transmitting the random accesschannel. Therefore, it is possible to increase the information amountnotified on the random access channel.

(13) Still furthermore, in the mobile communication system of theinvention, the mobile station apparatus is characterized by setting, asthe transmission control information, the transmission powercorresponding to the quality information indicator and the signaturecorresponding to the transmission reason, and transmitting the randomaccess channel using the transmission control information.

Thus, the mobile station apparatus sets, as the transmission controlinformation, the transmission power corresponding to the qualityinformation indicator and the signature corresponding to thetransmission reason, and is thereby capable of implicitly notifying thebase station apparatus of the quality information indicator intransmitting the random access channel, and the transmission reason ofthe random access channel. Therefore, it is possible to increase theinformation amount notified on the random access channel.

(14) Further, a mobile station apparatus of the invention is a mobilestation apparatus that communicates with a base station apparatus, andis characterized by having transmission control information settingdevice to set transmission control information about a random accesschannel based on at least one information of a measured qualityinformation indicator and a transmission reason of the random accesschannel, and transmitting device to transmit the random access channelusing the transmission control information, where the transmissioncontrol information includes one of a transmission frequency region,transmission power and a signature of the random access channel or acombination thereof.

Thus, the mobile station apparatus sets transmission control informationabout a random access channel based on at least one information of ameasured quality information indicator and a transmission reason of therandom access channel, and transmits the random access channel using thetransmission control information. Further, the transmission controlinformation includes one of a transmission frequency region,transmission power and signature of the random access channel or acombination thereof. By this means, by setting, as the transmissioncontrol information, transmission power for not increasing interferenceto peripheral cells based on, for example, a quality informationindicator at the time the random access channel is transmitted, it ispossible to enhance the reception quality of the random access channelin the base station apparatus, and therefore, it is possible to improvethe delivery probability of the random access channel without increasingthe uplink intercell interference amount. Further, for example, byimplicitly notifying the quality information indicator using thetransmission frequency region of the random access channel, it ispossible to increase the information amount notified on the randomaccess channel.

(15) Furthermore, in the mobile station apparatus of the invention, thetransmission control information setting device is characterized bysetting, as the transmission control information, the transmissionfrequency region based on the quality information indicator, andpredetermined transmission power corresponding to the transmissionfrequency region.

Thus, the random access channel is transmitted using the transmissioncontrol information on which is set the transmission frequency regionbased on the quality information indicator and predeterminedtransmission power corresponding to the transmission frequency region,and it is thereby possible to enhance the reception quality of therandom access channel in the base station apparatus. By this means, itis possible to improve the delivery probability of the random accesschannel without increasing the uplink intercell interference amount.

Further, the mobile station apparatus sets the transmission frequencyregion based on the quality information indicator, and is therebycapable of implicitly notifying the base station apparatus of thequality information indicator in transmitting the random access channelthrough the transmission frequency region, and therefore, it is possibleto increase the information amount notified on the random accesschannel.

(16) Still furthermore, in the mobile station apparatus of theinvention, the transmission control information setting device ischaracterized by setting, as the transmission control information, thetransmission frequency region based on a combination of the qualityinformation indicator and the transmission reason, and predeterminedtransmission power corresponding to the transmission frequency region.

Thus, the random access channel is transmitted using the transmissioncontrol information on which is set the transmission frequency regionbased on a combination of the quality information indicator and thetransmission reason, and predetermined transmission power correspondingto the transmission frequency region, and it is thereby possible toenhance the reception quality of the random access channel in the basestation apparatus. By this means, it is possible to improve the deliveryprobability of the random access channel without increasing the uplinkintercell interference amount.

Further, the mobile station apparatus sets the transmission frequencyregion based on a combination of the quality information indicator andthe transmission reason, and is thereby capable of implicitly notifyingthe base station apparatus of the quality information indicator intransmitting the random access channel and the transmission reason ofthe random access channel through the transmission frequency region, andtherefore, it is possible to increase the information amount notified onthe random access channel.

(17) Moreover, in the mobile station apparatus of the invention, thetransmission control information setting device is characterized bysetting, as the transmission control information, the transmissionfrequency region based on the quality information indicator,predetermined transmission power corresponding to the transmissionfrequency region, and the signature based on the transmission reason.

Thus, the random access channel is transmitted using the transmissioncontrol information on which are set the transmission frequency regionbased on the quality information indicator, predetermined transmissionpower corresponding to the transmission frequency region, and thesignature based on the transmission reason, and it is thereby possibleto enhance the reception quality of the random access channel in thebase station apparatus. By this means, it is possible to improve thedelivery probability of the random access channel without increasing theuplink intercell interference amount.

Further, the mobile station apparatus sets the transmission frequencyregion based on the quality information indicator, while further settingthe signature based on the transmission reason, is thereby capable ofimplicitly notifying the base station apparatus of the qualityinformation indicator in transmitting the random access channel throughthe transmission frequency region, and of implicitly notifying the basestation apparatus of the transmission reason of the random accesschannel through the signature, and therefore, it is possible to increasethe information amount notified on the random access channel.

(18) Further, in the mobile station apparatus of the invention, thetransmission control information setting device is characterized bysequentially repeating retransmission procedures in the transmissionfrequency region corresponding to the quality information indicatorlower than a measurement value, in retransmitting the random accesschannel.

Thus, in retransmitting the random access channel, since retransmissionprocedures are sequentially repeated in the transmission frequencyregion corresponding to the quality information indicator lower than ameasurement value, even when the random access channel cannot betransmitted with the measurement value, it is possible to vary thetransmission frequency region as appropriate, and to retransmit therandom access channel in an environment for more facilitatingtransmission.

(19) Furthermore, in the mobile station apparatus of the invention, thetransmission control information setting device is characterized bysetting, as the transmission control information, the signature based onthe quality information indicator, the transmission frequency regionbased on the transmission reason, and the transmission powercorresponding to the transmission frequency region.

Thus, the random access channel is transmitted using the transmissioncontrol information on which are set the signature bas ed on the qualityinformation indicator, the transmission frequency region based on thetransmission reason, and the transmission power corresponding to thetransmission frequency region, and it is thereby possible to enhance thereception quality of the random access channel in the base stationapparatus. By this means, it is possible to improve the deliveryprobability of the random access channel without increasing the uplinkintercell interference amount.

Further, the mobile station apparatus sets the signature based on thequality information indicator, while further setting the transmissionfrequency region based on the transmission reason, and is therebycapable of implicitly notifying the base station apparatus of thequality information indicator in transmitting the random access channelthrough the signature, and implicitly notifying the base stationapparatus of the transmission reason of the random access channelthrough the transmission frequency region, and therefore, it is possibleto increase the information amount notified on the random accesschannel.

(20) Moreover, in the mobile station apparatus of the invention, thetransmission control information setting device is characterized bysetting, as the transmission control information, the transmissionfrequency region based on the transmission reason and predeterminedtransmission power corresponding to the transmission frequency region.

Thus, the random access channel is transmitted using the transmissioncontrol information on which set is the transmission frequency regionbased on the transmission reason and predetermined transmission powercorresponding to the transmission frequency region, and it is therebypossible to enhance the reception quality of the random access channelin the base station apparatus. By this means, it is possible to improvethe delivery probability of the random access channel without increasingthe uplink intercell interference amount.

Further, the mobile station apparatus sets the transmission frequencyregion based on the transmission reason, and is thereby capable ofimplicitly notifying the base station apparatus of the transmissionreason of the random access channel through the transmission frequencyregion, and therefore, it is possible to increase the information amountnotified on the random access channel.

(21) Further, in the mobile station apparatus of the invention, thetransmission control information setting device is characterized bysetting, as the transmission control information, predeterminedtransmission power corresponding to the quality information indicator.

Thus, the random access channel is transmitted using the transmissioncontrol information on which is set predetermined transmission powercorresponding to the quality information indicator, and it is therebypossible to implicitly notify the base station apparatus of the qualityinformation indicator in transmitting the random access channel.Therefore, it is possible to increase the information amount notified onthe random access channel.

(22) Furthermore, in the mobile station apparatus of the invention, thetransmission control information setting device is characterized bysetting, as the transmission control information, predeterminedtransmission power corresponding to the quality information indicator,and the signature based on the transmission reason.

Thus, the mobile station apparatus sets predetermined transmission powercorresponding to the quality information indicator, and the signaturebased on the transmission reason, and is thereby capable of implicitlynotifying the base station apparatus of the quality informationindicator in transmitting the random access channel and the transmissionreason of the random access channel. Therefore, it is possible toincrease the information amount notified on the random access channel.

(23) Further, a base station apparatus of the invention is a basestation apparatus that communicates with a mobile station apparatus, andis characterized by having receiving device to receive a random accesschannel transmitted from the mobile station apparatus, analysis deviceto analyze transmission control information notified on the randomaccess channel, and scheduling device to determine the state of themobile station apparatus from an analysis result of the analysis device,and performing scheduling corresponding to the state of the mobilestation apparatus.

Thus, the base station apparatus analyzes the transmission controlinformation notified on the random access channel, performs schedulingcorresponding to a state of the mobile station apparatus determined fromthe analysis result, and is thereby capable of performing optimalscheduling in response to the state of the mobile station apparatus thatvaries by the minute according to circumstances of a communicationchannel and the like.

(24) Furthermore, in the base station apparatus of the invention, thescheduling device is characterized by performing scheduling based on aposition of the transmission frequency region of the random accesschannel included in the transmission control information.

Thus, the base station apparatus performs scheduling based on a positionof the transmission frequency region of the random access channelincluded in the transmission control information. Therefore, by themobile station apparatus suitably setting the position of thetransmission frequency region corresponding to the state of the mobilestation apparatus, the base station apparatus is capable of performingoptimal scheduling in response to the information provided from themobile station apparatus.

(25) Still furthermore, in the base station apparatus of the invention,the scheduling device is characterized by performing scheduling based ona position of the transmission frequency region and a number of asignature of the random access channel included in the transmissioncontrol information.

Thus, the base station apparatus performs scheduling based on a positionof the transmission frequency region and a number of a signature of therandom access channel included in the transmission control information.Therefore, by the mobile station apparatus suitably setting the positionof the transmission frequency region and the number of the signaturecorresponding to the state of the mobile station apparatus, the basestation apparatus is capable of performing optimal scheduling inresponse to the information provided from the mobile station apparatus.

(26) Moreover, in the base station apparatus of the invention, thescheduling device is characterized by performing scheduling based onreception quality of the random access channel received from the mobilestation apparatus.

Thus, the base station apparatus performs scheduling based on thereception quality of the random access channel received from the mobilestation apparatus. Therefore, for example, only by the mobile stationapparatus transmitting the random access channel with beforehandnegotiated transmission power, the base station apparatus is capable ofperforming optimal scheduling in response to the state of the mobilestation apparatus.

(27) Further, in the base station apparatus of the invention, thescheduling device is characterized by performing scheduling based onreception quality of the random access channel received from the mobilestation apparatus and a number of a signature of the random accesschannel included in the transmission control information.

Thus, the base station apparatus performs scheduling based on thereception quality of the random access channel received from the mobilestation apparatus, and the number of the signature. Therefore, forexample, only by the mobile station apparatus suitably setting thenumber of the signature corresponding to the state of the mobile stationapparatus and transmitting the random access channel with beforehandnegotiated transmission power, the base station apparatus is capable ofperforming optimal scheduling in response to the state of the mobilestation apparatus.

(28) Further, a random access channel transmitting method of theinvention is a method of transmitting a random access channel from amobile station apparatus that communicates with a base stationapparatus, and is characterized in that the mobile station apparatusdetermines transmission control information about a random accesschannel based on a state of the mobile station apparatus at the time oftransmitting the random access channel, and that the base stationapparatus determines the state of the mobile station apparatus based onthe transmission control information notified on the random accesschannel, and performs scheduling corresponding to the state of themobile station apparatus.

Thus, the mobile station apparatus sets transmission control informationof a random access channel based on a state of the mobile stationapparatus, while the base station apparatus performs schedulingcorresponding to the state of the mobile station apparatus based on thetransmission control information. According to this means, by settingthe transmission control information of the random access channel basedon, for example, as a state of the mobile station, quality informationindicator at the time the random access channel is transmitted, whilefurther setting, as the transmission control information of the randomaccess channel, transmission power for not increasing interference toperipheral cells, it is possible to enhance the reception quality of therandom access channel in the base station apparatus, and therefore, itis possible to improve the delivery probability of the random accesschannel without increasing the uplink intercell interference amount.Further, for example, by implicitly notifying the quality informationindicator using the transmission frequency region of the random accesschannel, it is possible to increase the information amount notified onthe random access channel.

Advantageous Effect of the Invention

According to the present invention, it is possible to improve thedelivery probability of a random access channel, while increasing theinformation amount notified on the random access channel.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing an example of a configuration of amobile station apparatus included in a mobile communication systemaccording to Embodiment 1 of the present invention;

FIG. 2 is a block diagram showing an example of a configuration of abase station apparatus included in the mobile communication systemaccording to Embodiment 1;

FIG. 3 is a diagram to explain the relationship between a transmissionfrequency region and transmission power of a RACH in Embodiment 1;

FIG. 4 is a diagram to explain an example of correspondence between aCQI of the mobile station and the transmission frequency region of theRACH in Embodiment 1;

FIG. 5 is a diagram to explain an example of correspondence between aRACH transmission reason of the mobile station and the transmissionfrequency region of the RACH in Embodiment 1;

FIG. 6 is a diagram to explain an example of correspondence between thetransmission frequency region of the RACH, and a CQI and RACHtransmission reason of the mobile station in Embodiment 1;

FIG. 7 is a diagram to explain an example of correspondence between thetransmission frequency region of the RACH and a number of a signature,and the CQI and RACH transmission reason of the mobile station inEmbodiment 1;

FIG. 8 is a diagram to explain an example of correspondence between thetransmission frequency region of the RACH and the number of thesignature, and the RACH transmission reason and CQI of the mobilestation in Embodiment 1;

FIG. 9 is a diagram showing an example of a retransmission method of theRACH in the case of notifying the CQI of the mobile station with thetransmission frequency region of the RACH in Embodiment 1;

FIG. 10 is a diagram showing an example of setting transmission power inthe case that a transmission bandwidth of the RACH is wider than afrequency region used by the mobile station in uplink transmission inEmbodiment 1;

FIG. 11 is a diagram showing an example of setting transmission power inthe case that the transmission bandwidth of the RACH is narrower thanthe frequency region used by the mobile station in uplink transmissionin Embodiment 1;

FIG. 12 is a diagram to explain the relationship between transmissionfrequency regions of the RACH transmission and transmission poweraccording to Embodiment 2;

FIG. 13 is a diagram showing an example of estimating the CQI of themobile station from a reception power value of the RACH in Embodiment 2;

FIG. 14 is a diagram to explain an example of correspondence between theCQI of the mobile station and transmission power of the RACH inEmbodiment 2;

FIG. 15 is a diagram to explain another example of correspondencebetween the CQI of the mobile station and transmission power of the RACHin Embodiment 2;

FIG. 16 is a diagram to explain an example of correspondence betweentransmission power of the RACH and a number of a signature, and the CQIand RACH transmission reason in Embodiment 2;

FIG. 17 is a flowchart to explain transmission procedures in randomaccess in the W-CDMA system;

FIG. 18 is a diagram showing an example of channel mapping of the RACHproposed in EUTRA;

FIG. 19 is a diagram showing an example of a method of notifying thebase station of the CQI and transmission reason of the RACH using asignature number at the time of random access;

FIG. 20 is a diagram showing the positional relationship between a celland mobile station; and

FIG. 21 is a diagram showing an example of applying different targetquality for each frequency region that is divided for interferencecontrol in uplink frequency regions.

DESCRIPTION OF SYMBOLS

-   101, 201 Receiving section-   102, 202 Channel demodulation section-   103, 203 Schedule section-   104, 204 Decoding section-   105, 205 Control signal processing section-   106 Channel measuring section-   107, 207 Upper layer-   108 CQI calculating section-   109, 208 Coding section-   110 Random access control section-   111, 209 Channel modulation section-   112, 210 Transmission power control section-   113, 211 Transmitting section-   206 Random access analysis section

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the invention will be described below with reference toaccompanying drawings.

Embodiment 1

FIG. 1 is a block diagram showing an example of a configuration of amobile station apparatus (hereinafter, referred to as a “mobilestation”) included in a mobile communication system (hereinafter,referred to as a “communication system” as appropriate) according toEmbodiment 1 of the present invention. In the mobile station as shown inFIG. 1, a receiving section 101 receives a reception signal. Thereception signal received in the receiving section 101 is output to achannel demodulation section 102, demodulated based on schedulinginformation input from a schedule section 103, and classified into adata channel, control channel, and downlink common pilot channel(DL-CPICH). With respect to each classified data, the data channel issent to a decoding section 104, the control channel is sent to a controlsignal processing section 105, and the downlink common pilot channel issent to a channel measuring section 106. The decoding section 104extracts user data to send to an upper layer 107. The control signalprocessing section 105 extracts control data to send to the upper layer107.

In addition, scheduling information included in the control channel issent to the schedule section 103. The channel measuring section 106measures reception quality of the downlink common pilot channel to sendto the upper layer 107 as measurement data, while sending the receptionquality to a CQI calculating section 108. The CQI calculating section108 calculates a CQI from the reception quality to send to the upperlayer 107 as a CQI value. Upon receiving the CQI value, the upper layer107 sets random access information as transmission control informationincluding information such as the reception quality (CQI) measuredimmediately before RACH transmission, RACH transmission reason and thelike. In other words, the upper layer 107 functions as the transmissioncontrol information setting device.

In addition, as a method of calculating the CQI in the CQI calculatingsection 108, there are a method of obtaining every time from aninstantaneous value of the DL-CP ICH, and another method of averagingfor predetermined reception time to obtain, and either method may beused. Further, there are a method of obtaining on a DL-CPICH bass andanother method of averaging over some reception band, and both methodsare included herein. Furthermore, even when another CQI calculatingmethod is used other than the above-mentioned methods, the subjectmatter of the present invention is not affected.

Meanwhile, with the onset of a sending request from the upper layer 107,the user data and control data is input to a coding section 109 andencoded as transmission data. Further, the upper layer 107 inputs thescheduling information to the schedule section 103. At the time ofrandom access, the upper layer 107 sends random access informationincluding information such as the reception quality (CQI) measuredimmediately before RACH transmission, RACH transmission reason and thelike to a random access control section 110. The random access controlsection 110 sends to the schedule section 103 the scheduling informationsuch as a frequency region for transmitting a random access channel,transmission power to set and the like. The user data and control dataencoded in the coding section 109 is input to a channel modulationsection 111. According to the scheduling information sent from theschedule section 103, the channel modulation section 111 performsmodulation processing on the transmission data with a suitablemodulation scheme, and concurrently, performs mapping onto a suitableuplink channel. The modulated data is subjected to power controlaccording to the channel in a transmission power control section 112 andtransmitted from a transmitting section 113. In addition, othercomponents of the mobile station are not related to the presentinvention and omitted. Further, the operation of each block is subjectedto centralized control by the upper layer 107.

FIG. 2 is a block diagram showing an example of a configuration of abase station apparatus (hereinafter, referred to as a “base station”)included in the mobile communication system according to Embodiment 1.In the base station as shown in FIG. 2, a receiving section 201 receivesa reception signal (transmission signal from a mobile station). Thereception signal received in the receiving section 201 is output to achannel demodulation section 202, demodulated based on schedulinginformation input from a schedule section 203, and classified into adata channel, control channel, and random access channel. With respectto each demodulated data, the data channel is sent to a decoding section204, the control channel is sent to a control signal processing section205, and the random access channel is sent to a random access analysissection 206. The decoding section 204 performs decoding processing onuser data to send to an upper layer 207. The control signal processingsection 205 extracts control data to send to the upper layer 207.Further, control data associated with control of the channeldemodulation section 202 and decoding section 204 is sent to each block.The random access analysis section 206 analyzes a frequency region inwhich the random access channel was transmitted, signature of a RACHPreamble, and reception quality of the random access channel, and sendsthe analyzed data to the upper layer 207. The upper layer 207 judges astate of the mobile station based on the analyzed data, whiledetermining optimal scheduling information corresponding to the state ofthe mobile station. In other words, the upper layer 207 functions as thescheduling device.

Meanwhile, with the onset of a sending request from the upper layer 207,the user data and control data is input to a coding section 208.Further, the upper layer inputs the scheduling information to theschedule section 203. The user data and control data encoded in thecoding section 208 is input to a channel modulation section 209.According to the scheduling information input from the schedule section203, the channel modulation section 209 performs modulation processingon the transmission data with a suitable modulation scheme, andconcurrently, performs mapping onto a suitable downlink channel. Themodulated data is subjected to power control according to the channel ina transmission power control section 210 and transmitted from atransmitting section 211. In addition, other components of the basestation are not related to the present invention and omitted. Further,the operation of each block is subjected to centralized control by theupper layer 207.

FIG. 3 is a diagram to explain uplink frequency regions used in RACHtransmission, and transmission power in the transmission in the mobilecommunication system according to Embodiment 1. In FIG. 3, BW representsa transmission/reception bandwidth of the base station, and in EUTRA,the transmission/reception bandwidth may vary with the base station (forexample, 1.25 MHz, 2.5 MHz, 5 MHz, 10 MHz and 20 MHz). F1, F2 . . . , Fn(n is a natural number except 0) are frequency regions comprised of aplurality of subcarriers divided from the transmission/receptionbandwidth of the base station, and a frequency region to use isdetermined according to the reception quality of the mobile station.FIG. 3 shows that mobile stations are divided into n groups according tothe reception quality. P1, P2, . . . , Pn represent maximum power valuesallowing transmission without increasing interference to peripheralcells in respective frequency regions. In addition, P1, P2, . . . , Pnare set not to exceed the maximum transmission power of mobile stationsin consideration of the capability of mobile stations (UE capability).Each of STEP1, STEP2, . . . , STEPn−1 represents a difference betweensome frequency region and an adjacent frequency region. In addition, F1,F2, . . . , Fn may have the same values or different values. Similarly,STEP1, STEP2, . . . , STEPn−1 may have the same values or differentvalues. Further, the values may differ for each base station.

When transmitting a RACH to the base station, the mobile station selectsone from among frequency regions F1 to Fn according to the informationfor implicitly notifying the base station. At this time, as thetransmission power of the RACH, the mobile station sets maximumtransmission power P1-Pn corresponding to the selected frequency region.In the communication system according to Embodiment 1, mutuallydifferent maximum transmission power that does not increase interferenceto peripheral cells is beforehand determined for each frequency region,and as the transmission control information, by setting a transmissionfrequency region, while further setting the maximum transmission powercorresponding to the frequency region, it is possible to enhance thereception quality of the random access channel in the base station.Therefore, it is possible to improve the delivery probability of therandom access channel without increasing the uplink intercellinterference amount. Variations thereof are shown below.

FIG. 4 is a diagram to explain an example of correspondence between atransmission frequency region of the RACH and CQI in the case oftransmitting a CQI (more specifically, Downlink CQI) as the informationto implicitly notify the base station from the mobile station. In FIG.4, there are eight classified regions (n=8) as the frequency region, andCQIs are classified into five stages i.e. Very high, High, Medium, Low,and Very Low. The lower number or higher number of classifications isallowed. Further, the CQI to classify may be evenly classed with respectto the range of the CQI, or the range may be varied corresponding to thedistribution density of CQI. Furthermore, the range may be varied witheach base station.

The mobile station transmits the RACH to the base station in thefrequency region corresponding to the CQI measured immediately beforeRACH transmission. When there is a plurality of corresponding frequencyregions, the mobile station randomly selects one from among the regions.In other words, herein, the transmission control information at the timeof RACH transmission is set based on the CQI as the state of the mobilestation, and the transmission frequency region and transmission power ofthe RACH is set as the transmission control information at the time ofRACH transmission. In the example as shown in FIG. 4, when the CQImeasured immediately before is “High”, F2 and F3 can be selected as thefrequency region. The mobile station randomly selects either one of F2and F3, sets transmission power P2 when the selected frequency region isF2 or transmission power P3 when the selected frequency region is F3,and transmits the RACH.

The base station receiving the RACH transmitted with the transmissioncontrol information thus set is capable of grasping the CQI of themobile station from the frequency region in which the RACH is received.Using thus recognized CQI of the mobile station, the base stationsuitably determines distribution of radio resources to allocate to themobile station, modulation scheme to use and the like to performscheduling. For example, when receiving the RACH from a mobile stationwith a high CQI, it is possible to perform scheduling such that moreradio resources than usual are allocated to improve throughput, and thatdata transmission is started using a modulation scheme with a hightransmission rate. On the other hand, when receiving the RACH from amobile station with a poor CQI, it is possible to perform schedulingsuch that radio resources are limited to be less than usual, and thatdata transmission is started using a modulation scheme with a high errorcorrecting capability.

Particularly, in the example as shown in FIG. 4, since the transmissionfrequency region of the RACH is set based on the CQI at the time of RACHtransmission, it is possible to implicitly notify the base station ofthe CQI in transmitting the RACH through the transmission frequencyregion, and therefore, it is possible to increase the information amountnotified on the RACH.

FIG. 5 is a diagram to explain an example of correspondence between atransmission frequency region of the RACH and reason of RACHtransmission (hereinafter, referred to as a “RACH transmission reason”as appropriate) in the case of transmitting the RACH transmission reasonas the information to implicitly notify the base station from the mobilestation. In FIG. 5, there are eight classified regions (n=8) as thefrequency region, and RACH transmission reasons are classified into fiveitems i.e. initial transmission, resource request, handover,intermittent transmission, and synchronization confirmation. The loweror higher number of classifications is allowed corresponding tocircumstances where the RACH is used. Considered as other RACHtransmission reasons are re-connection, urgent call issue and the like.

The mobile station determines a matter to be a reason of RACHtransmission from the state of the mobile station at the time of RACHtransmission and the like, and transmits the RACH to the base station inthe corresponding frequency region. When there is a plurality ofcorresponding frequency regions, the mobile station randomly selects onefrom among the regions. At this point, as shown in FIG. 3, the mobilestation sets transmission power associated with the selected frequencyregion. In other words, herein, the transmission control information atthe time of RACH transmission is set based on the RACH transmissionreason as the state of the mobile station, and the transmissionfrequency region and transmission power of the RACH is set as thetransmission control information at the time of RACH transmission. Inthe example as shown in FIG. 5, when the RACH transmission reason is“resource request”, F2 and F3 can be selected as the frequency region.The mobile station randomly selects either one of F2 and F3, setstransmission power P2 when the selected frequency region is F2 ortransmission power P3 when the selected frequency region is F3, andtransmits the RACH.

The base station receiving the RACH transmitted with the transmissioncontrol information thus set is capable of grasping the RACHtransmission reason from the frequency region in which the RACH isreceived. Using thus recognized RACH transmission reason of the mobilestation, the base station suitably determines distribution of radioresources to allocate to the mobile station, modulation scheme to useand the like to perform scheduling. For example, when the RACHtransmission reason is initial transmission, it is possible to performscheduling such that relatively few radio resources are allocatedwithout allocating many radio resources from the beginning. Further,when the RACH transmission reason is handover, since it is necessary touse current radio resources and modulation scheme similarly in ahandover-destination cell, it is possible to perform scheduling suchthat current scheduling is continued without needing additionalinformation.

Particularly, in the example as shown in FIG. 5, since the transmissionfrequency region of the RACH is set based on the transmission reason ofthe RACH, it is possible to implicitly notify the base station of thetransmission reason of the to RACH through the transmission frequencyregion of the RAC, and therefore, it is possible to increase theinformation amount notified on the RACH.

FIG. 6 is a diagram to explain an example of correspondence between atransmission frequency region of the RACH and CQI and RACH transmissionreason in the case of transmitting both of the CQI and RACH transmissionreason as the information to implicitly notify the base station from themobile station. In FIG. 6, as the frequency region, there are sixteenclassified regions (n=16). The CQI and RACH transmission reason areclassified respectively in the same way as in FIGS. 4 and 5, but thelower or higher of classifications than in FIG. 6 is allowed.

In addition, as shown in FIG. 6, the number of classes of the frequencyregion may be varied for each RACH transmission reason. In FIG. 6, CQIsare classified into five classes when the RACH transmission reason isinitial transmission, while being classified into three classes in thecase of a resource request, and being classified into two classes in thecase of synchronization confirmation. In this case, the number ofclasses for each RACH transmission reason, and thresholds used toclassify are different from one another, and beforehand notified orbroadcast to the mobile station.

The mobile station transmits the RACH to the base station in thefrequency region corresponding to the CQI measured immediately beforeRACH transmission and RACH transmission reason. At this point, as shownin FIG. 3, the mobile station sets transmission power corresponding tothe selected frequency region. In other words, herein, the transmissioncontrol information at the time of RACH transmission is set based on theCQI and the RACH transmission reason as the state of the mobile station,and the transmission frequency region and transmission power of the RACHis set as the transmission control information at the time of RACHtransmission. In the example as shown in FIG. 6, when the CQI measuredimmediately before is “High” and RACH transmission reason is “resourcerequest”, F6 is selected as the frequency region. The mobile stationsets transmission power P6 corresponding to F6 that is the selectedfrequency region, and transmits the RACH.

The base station receiving the RACH transmitted with the transmissioncontrol information thus set is capable of grasping the CQI and RACHtransmission reason of the mobile station from the frequency region inwhich the RACH is received. Using thus recognized CQI and RACHtransmission reason of the mobile station, the base station is capableof suitably determining distribution of radio resources to allocate tothe mobile station, modulation scheme to use and the like to performscheduling.

Particularly, in the example as shown in FIG. 6, since the transmissionfrequency region of the RACH is set based on a combination of the CQI atthe time of RACH transmission and transmission reason of the RACH, it ispossible to implicitly notify the base station of a quality informationindicator in transmitting the RACH and the transmission reason of theRACH through the transmission frequency region, and therefore, it ispossible to increase the information amount notified on the RACH.

FIG. 7 is a diagram to explain an example of correspondence between atransmission frequency region of the RACH and a number of a signature,and the CQI and RACH transmission reason in the case of transmittingboth of the CQI and RACH transmission reason as the information toimplicitly notify the base station from the mobile station. In FIG. 7,there are eight classified regions (n=8) as the frequency region. TheCQI and RACH transmission reason are classified respectively in the sameway as in FIGS. 4 and 5, but the lower or higher of classifications thanin FIG. 7 is allowed.

The mobile station selects a frequency region corresponding to the CQImeasured immediately before RACH transmission, and selects a signatureto form a RACH preamble from the RACH transmission reason. When there isa plurality of corresponding frequency regions or signatures, the mobilestation randomly selects one from among them. At this point, as shown inFIG. 3, the mobile station sets transmission power corresponding to theselected frequency region. In other words, herein, the transmissioncontrol information at the time of RACH transmission is set based on theCQI and the RACH transmission reason as the state of the mobile station,and the transmission frequency region, transmission power and signatureof the RACH is set as the transmission control information at the timeof RACH transmission. In the example as shown in FIG. 7, when the CQImeasured immediately before is “High” and RACH transmission reason is“resource request”, F2 and F3 can be selected as the frequency region,and “11” to “15” can be selected as the signature. The mobile stationrandomly selects one signature from “11” to “15”, further randomlyselects either one frequency region F2 or F3, sets transmission power P2when the selected frequency region is F2, or transmission power P3 whenthe selected frequency region is F3, and transmits the RACH.

In addition, as a method of transmitting a RACH preamble including theselected signature, considered are a method of transmitting only a RACHpreamble, and another method of transmitting a RACH preamble and RACHmessage at the same time. However, the invention is not affected in thecase of using either method, and therefore, both methods are allowed.

The base station receiving the RACH transmitted with the transmissioncontrol information thus set is capable of grasping the CQI of themobile station from the frequency region in which the RACH is received.Further, the base station is capable of grasping the RACH transmissionreason of the mobile station from the signature number. Using thusrecognized CQI and RACH transmission reason of the mobile station, thebase station is capable of suitably determining distribution of radioresources to allocate to the mobile station, modulation scheme to useand the like to perform scheduling.

Particularly, in the example as shown in FIG. 7, since the transmissionfrequency region of the RACH is set based on the CQI at the time of RACHtransmission, while the signature is set based on the transmissionreason of the RACH, it is possible to implicitly notify the base stationof the CQI in transmitting the RACH through the transmission frequencyregion, and to implicitly notify the base station of the transmissionreason of the RACH through the signature, and therefore, it is possibleto increase the information amount notified on the RACH.

FIG. 8 is a diagram to explain an example of correspondence between atransmission frequency region of the RACH and a number of a signature,and the RACH transmission reason and CQI in the case of transmittingboth of the CQI and RACH transmission reason as the information toimplicitly notify the base station from the mobile station. In FIG. 8,there are eight classified regions (n=8) as the frequency region. TheCQI and RACH transmission reason are classified respectively in the sameway as in FIGS. 4 and 5, but the lower or higher of classifications thanin FIG. 8 is allowed. Further, the CQI to classify may be evenly classedwith respect to the range of the CQI, or the range may be variedcorresponding to the distribution density of CQI. Furthermore, the rangemay be varied with each base station.

The mobile station selects a signature to form a RACH preamblecorresponding to the CQI measured immediately before RACH transmission,and selects a frequency region from the RACH transmission reason. Whenthere is a plurality of corresponding signatures or frequency regions,the mobile station randomly selects one from among them. At this point,as shown in FIG. 3, the mobile station sets transmission powercorresponding to the selected frequency region. In other words, herein,the transmission control information at the time of RACH transmission isset based on the CQI and the RACH transmission reason as the state ofthe mobile station, and further, the transmission frequency region,transmission power and signature of the RACH are set as the transmissioncontrol information at the time of RACH transmission. In the example asshown in FIG. 8, when the CQI measured immediately before is “High” andRACH transmission reason is “resource request”, “6” to “12” can beselected as the signature, and F3 and F4 can be selected as thefrequency region. The mobile station randomly selects one signature from“6” to “12”, further randomly selects either one frequency region F3 orF4, sets transmission power P3 when the selected frequency region is F3,or transmission power P4 when the selected frequency region is F4, andtransmits the RACH.

In addition, as a method of transmitting a RACH preamble including theselected signature, considered are a method of transmitting only a RACHpreamble, and another method of transmitting a RACH preamble and RACHmessage at the same time. However, the invention is not affected in thecase of using either method, and therefore, both methods are allowed.

The base station receiving the RACH transmitted with the transmissioncontrol information thus set is capable of grasping the CQI of themobile station from the signature number. Further, the base station iscapable of grasping the RACH transmission reason of the mobile stationfrom the frequency region in which the RACH is received. Using thusrecognized CQI and RACH transmission reason of the mobile station, thebase station is capable of suitably determining distribution of radioresources to allocate to the mobile station, modulation scheme to useand the like to perform scheduling.

Particularly, in the example as shown in FIG. 8, since the signature isset based on the CQI at the time of RACH transmission, while thetransmission frequency region is set based on the transmission reason ofthe RACH, it is possible to implicitly notify the base station of theCQI in transmitting the RACH through the signature, and to implicitlynotify the base station of the transmission reason of the RACH throughthe transmission frequency region, and therefore, it is possible toincrease the information amount notified on the RACH.

In addition, in FIGS. 4 to 8, CQIs, frequency regions (F1˜Fn), signaturenumbers, corresponding maximum transmission power (P1˜Pn), anddifferences (STEP1˜STEPn−1) in maximum transmission power, which areused for RACH transmission, are acquired before RACH transmission bybeing notified on the control channel from the base station, or byreceiving broadcast information. Further, the RACH transmission reasonis acquired by a mobile station determining a state of the mobilestation. Furthermore, the above-mentioned number of frequency regionsincluded in the CQI or RACH transmission reason is allowed to vary witheach base station. For example, in a base station just under whichexists a mobile station-density area, the collision probability of theRACH may be reduced by allocating the higher number of frequency regionsto CQI=Very high than other CQIs.

FIG. 9 is a diagram showing an example of a retransmission method of theRACH in the case of notifying the CQI with a transmission frequencyregion of the RACH. In addition, in FIG. 9, the frequency range isdivided into five frequency regions, and the frequency regionscorrespond to CQI=Very high, High, Medium, Low, Very low. Further, theCQI to classify may be evenly classed with respect to the range of theCQI, or the range may be varied corresponding to the distributiondensity of CQI. Furthermore, the range may be varied with each basestation.

When the CQI is notified with the transmission frequency region of theRACH (FIGS. 4 and 6), in the case where the mobile station cannotreceive ACK from the base station in response to RACH transmission, orthe mobile station receives NACK, the mobile station randomly selects asignature again, and retransmits a RACH preamble formed of the selectedsignature in the frequency region indicative of the same CQI. When themobile station cannot receive ACK even after repeating theretransmission m times (m is a natural number except 0), the mobilestation shifts the frequency region to another region so that the CQI islowered by “1”, and resets the transmission power to performretransmission. In addition, when the class of CQI is already the rangeof the lowest value (Very low in FIG. 9), the retransmission isperformed in the same frequency region. In addition, with respect to thenumber m of retransmissions, the number is beforehand defined, ornotified on the control channel from the base station, or the broadcastinformation is received, and thus, the mobile station acquires thenumber before RACH transmission.

When the CQI is notified with the transmission frequency region of theRACH and the RACH transmission reason is notified with the signature(FIG. 7), in the case where the mobile station cannot receive ACK fromthe base station in response to RACH transmission, or the mobile stationreceives NACK, the mobile station randomly selects one from amongsignatures corresponding to the RACH transmission reason, andretransmits a RACH preamble formed of the selected signature in thefrequency region indicative of the same CQI. When the mobile stationcannot receive ACK even after repeating the retransmission m times (m isa natural number except 0), the mobile station shifts the frequencyregion to another region so that the CQI is poorer by “1”, and resetsthe transmission power to perform retransmission. In addition, when theclass of CQI is already the range of the lowest value, theretransmission is performed in the same frequency region.

FIG. 9 is the example showing the case (FIGS. 4, 6 and 7) of notifyingthe CQI with the frequency transmission region of the RACH, andretransmission methods will be described below in the case where the CQIis not notified with the frequency transmission region of the RACH.

When the RACH retransmission reason is notified with the transmissionfrequency region of the RACH (FIG. 5), in the case where the mobilestation cannot receive ACK from the base station in response to RACHtransmission, or the mobile station receives NACK, the mobile stationrandomly selects a signature again, and retransmits a RACH preambleformed of the selected signature in the frequency region indicative ofthe same RACH transmission reason.

When the CQI is notified with the signature of the RACH and the RACHtransmission reason is notified with the transmission frequency region(FIG. 8), in the case where the mobile station cannot receive ACK fromthe base station in response to RACH transmission, or the mobile stationreceives NACK, the mobile station randomly selects one from amongsignatures corresponding to the CQI of the mobile station, andretransmits a RACH preamble formed of the selected signature in thefrequency region indicative of the same RACH transmission reason. Whenthe mobile station cannot receive ACK even after repeating theretransmission m times (m is a natural number except 0), the mobilestation shifts the signature to another signature so that the CQI ispoorer by “1”, and performs retransmission. In addition, when the classof CQI is already the range of the lowest value, the retransmission isperformed in the same frequency region.

Meanwhile, FIG. 3 shows an example of the case that the transmissionbandwidth used in RACH transmission is matched with a bandwidth of thefrequency region used by the mobile station in uplink transmission, andanother example will be described below that the bandwidths aredifferent from one another.

FIG. 10 is a diagram showing an example of setting transmission power inthe case that the transmission bandwidth used in RACH transmission iswider than a bandwidth of the frequency region used by the mobilestation in uplink transmission. In FIG. 10, assuming that the frequencyregion used by the mobile station in uplink transmission is BW_c, andthat the transmission bandwidth of the RACH is BW_r, the relationship ofBW_c<BW_r holds. In this case, as the transmission power of the RACH,the mobile station sets the lowest power value included in the frequencyregion of the RACH. In the example as shown in FIG. 10, when the mobilestation uses RACH_1, F1 to F3 are included as the frequency region. Themobile station transmits the RACH to the base station with transmissionpower P1 that is the lowest power value corresponding to F3.

FIG. 11 is a diagram showing an example of setting transmission power inthe case that the transmission bandwidth used in RACH transmission isnarrower than a bandwidth of the frequency region used by the mobilestation in uplink transmission. In FIG. 11, as in FIG. 10, assuming thatthe frequency region used by the mobile station in uplink transmissionis BW_c, and that the transmission bandwidth of the RACH is BW_r, therelationship of BW_c>BW_r holds. In this case, as the transmission powerof the RACH, the mobile station sets the lowest power value included inthe frequency region of the RACH. In the example as shown in FIG. 11,when the mobile station uses RACH_2, F4 and F5 are included as thefrequency region. The mobile station transmits the RACH to the basestation with transmission power P5 that is the lowest power valuecorresponding to F5.

Thus, according to the communication system according to Embodiment 1,mutually different maximum transmission power that does not increaseinterference to peripheral cells is beforehand determined for eachtransmission frequency region of the RACH, the transmission frequencyregion is set as the transmission control information, while the maximumtransmission power is set corresponding to the frequency region, it isthereby possible to enhance the reception quality of the RACH in thebase station, and therefore, it is possible to improve the deliveryprobability of the RACH without increasing the uplink intercellinterference amount. In addition, any power values may be set other thanthe maximum transmission power, as long as the power values do notincrease interference to peripheral cells.

Further, for example, since the transmission frequency region is setbased on the CQI at the time of RACH transmission, it is possible toimplicitly notify the base station of the CQI at the time of RACHtransmission through the transmission frequency region, and therefore,it is possible to increase the information amount notified on the RACH.Particularly, the number of usable signatures is not significantlylimited unlike the conventional way, and it is thereby possible todrastically reduce the collision probability of the RACH.

Embodiment 2

In the communication system according to Embodiment 1, when thefrequency bandwidth of the base station is a relatively narrow bandwidthsuch as, for example, 1.25 MHz and 2.5 MHz, and is not sufficiently wideas compared with the transmission bandwidth of the RACH, there is thepossibility that required information cannot be notified to the basestation. Therefore, in a communication system according to Embodiment 2,the information is implicitly notified to the base station with thetransmission power of the RACH in the mobile station, in other words,the reception power (reception quality) of the RACH in the base station.In addition, configurations of the mobile station and base stationconstituting the communication system according to Embodiment 2 are thesame as those in the communication system according to Embodiment 1, anddescriptions thereof are omitted.

FIG. 12 is a diagram to explain uplink frequency regions used in RACHtransmission, and transmission power in the transmission in the mobilecommunication system according to Embodiment 2. In FIG. 12, BWrepresents a transmission/reception bandwidth of the base station, andin EUTRA, the transmission/reception bandwidth may vary with the basestation (for example, 1.25 MHz, 2.5 MHz, 5 MHz, 10 MHz and 20 MHz). F1,F2, . . . , Fn (n is a natural number except j) are frequency regionscomprised of a plurality of subcarriers divided from thetransmission/reception bandwidth of the base station, and a frequencyregion to use is determined according to the reception quality of themobile station. FIG. 12 shows that mobile stations are divided into ngroups according to the reception quality. P1, P2, . . . , Pn representpower values allowing transmission without increasing interference toperipheral cells in respective frequency regions. Each of STEP1, STEP2,. . . , STEPn−1 represents a difference between some frequency regionand an adjacent frequency region. In addition, F1, F2, . . . , Fn mayhave the same values or different values. Similarly, STEP1, STEP2, . . ., STEPn−1 may have the same values or different values. Further, thevalues may differ for each base station.

When transmitting a RACH to the base station, the mobile station setsthe transmission power of the RACH at a value included in the range oftwo adjacent values among P1 to Pn according to the information toimplicitly notify the base station, and transmits the RACH in anarbitrary frequency region. The RACH transmitted with the transmissionpower among P1 to Pn is subjected to distance attenuation and the effectof peripheral-cell interference until the time of reaching the basestation, and received in the base station in the range of receptionpower thresholds Rx1 to Rxn as shown in FIG. 13. The base stationcompares the reception power value of the received RACH with theaforementioned reception power thresholds Rx1 to Rxn, and estimates theCQI of the mobile station. FIG. 13 shows the case that the RACH isreceived with the reception power between reception power thresholds Rx2to Rx3 in frequency region F3. In this case, the base station determinesthat the CQI of the mobile station is CQI_2.

FIG. 14 is a diagram to explain an example of correspondence betweentransmission power of the RACH and CQI in the case of transmitting a CQI(more specifically, Downlink CQI) as the information to implicitlynotify the base station from the mobile station. In FIG. 14, there aresix regions (n=6) as the frequency region, and CQls are classified intofive stages i.e. Very high, High, Medium, Low, and Very Low. The lowernumber or higher number of classifications is allowed. Further, the CQIto classify may be evenly classed with respect to the range of the CQI,or the range may be varied corresponding to the distribution density ofCQI. Furthermore, the range may be varied with each base station.

The mobile station sets the transmission power of the RACH to beincluded in the range corresponding to the CQI measured immediatelybefore RACH transmission, and transmits the RACH to the base station. Inother words, herein, the transmission control information at the time ofRACH transmission is set based on the CQI as the state of the mobilestation, and the transmission power of the RACH is set as thetransmission control information at the time of RACH transmission. Inthe example as shown in FIG. 14, when the CQI measured immediatelybefore is “High”, the mobile station sets transmission power value Pmeeting P2>P≥P3 as the transmission power, and transmits the RACH to thebase station. At this point, the frequency region to use is randomly toselected from F1 to F6.

In addition, the transmission power may be set as the maximumtransmission power as shown in FIG. 15, without being set from somerange as shown in FIG. 14. In the example as shown in FIG. 15, when theCQI measured immediately is before is High, the mobile station setstransmission power P2 and transmits the RACH to the base station.Further, it is allowed to set power values other than theabove-mentioned values, as long as the power values enable the CQI ofthe mobile station to be determined from the reception power value anddo not increase interference to peripheral cells.

The base station receiving the RACH transmitted with the transmissioncontrol information thus set compares the reception power of thereceived RACH with the reception power threshold, and is thereby capableof grasping the CQI of the mobile station. In addition, theabove-mentioned reception power thresholds are beforehand defined, ornotified from a station higher than the base station. Using therecognized CQI of the mobile station, the base station is capable ofsuitably determining distribution of radio resources to allocate to themobile station, modulation scheme to use and the like to performscheduling.

Particularly, in the example as shown in FIG. 14 or 15, since the RACHis transmitted using the transmission control information with thetransmission power of the RACH set based on the CQI at the time of RACHtransmission, it is possible to implicitly notify the base station ofthe CQI at the time of RACH transmission. Therefore, it is possible toincrease the information amount notified on the random access channel.

FIG. 16 is a diagram to explain an example of correspondence betweentransmission power of the RACH and a signature number, and the CQI andRACH transmission reason in the case of transmitting both of the CQI(Downlink CQI) and RACH transmission reason as the information toimplicitly notify the base station from the mobile station. In FIG. 16,there are six frequency regions (n=6) as the frequency region, and CQIsare classified into five stages i.e. Very high, High, Medium, Low, andVery Low. The lower number or higher number of classifications isallowed. Further, the CQI to classify may be evenly classed with respectto the range of the CQI, or the range may be varied corresponding to thedistribution density of CQI. Furthermore, the range may be varied witheach base station.

The mobile station sets the transmission power of the RACH to beincluded in the range corresponding to the CQI measured immediatelybefore RACH transmission, and selects a signature to form a RACHpreamble from the RACH transmission reason. When there is a plurality ofcorresponding signatures, the mobile station selects one from among thesignatures. In other words, herein, the transmission control informationat the time of RACH transmission is set based on the CQI and the RACHtransmission reason as the state of the mobile station, and further, thetransmission power and signature of the RACH is set as the transmissioncontrol information at the time of RACH transmission. In addition, thetransmission power of the RACH may be set at a unique power value as themaximum transmission power as shown in FIG. 15. Further, it is allowedto set power values other than the above-mentioned values, as long asthe power values enable the CQI of the mobile station to be determinedfrom the reception power value and do not increase interference toperipheral cells.

In addition, as a method of transmitting a RACH preamble including theselected signature, considered are a method of transmitting only a RACHpreamble, and another method of transmitting a RACH preamble and RACHmessage at the same time. However, the invention is not affected in thecase of using either method, and therefore, both methods are allowed.

The base station receiving the RACH transmitted with the transmissioncontrol information thus set compares the reception power of thereceived RACH with the reception power threshold, and is thereby capableof grasping the CQI of the mobile station. Further, the mobile stationis capable of grasping the RACH transmission reason from the signaturenumber. In addition, the above-mentioned reception power thresholds arebeforehand defined, or notified from a stat ion higher than the basestation. Using the recognized CQI and RACH transmission reason of themobile station, the base station is capable of suitably determiningdistribution of radio resources to allocate to the mobile station,modulation scheme to use and the like to perform scheduling.

Particularly, in the example as shown in FIG. 16, since the transmissionpower is set based on the CQI at the time of RACH transmission, and thesignature is set based on the transmission reason of the RACH, it ispossible to implicitly notify the base station of the CQI at the time ofRACH transmission and the transmission reason of the RACH. Therefore, itis possible to increase the information amount notified on the randomaccess channel.

In FIGS. 14 to 16, CQIs, frequency regions (F1˜Fn), signature numbers,corresponding maximum transmission power (P1˜Pn), and differences(STEP1˜STEPn−1) in maximum transmission power, which are used for RACHtransmission, are acquired before RACH transmission by being notifiedfrom the base station on the control channel, or by receiving broadcastinformation. Further, the RACH transmission reason is acquired by amobile station determining a state of the mobile station. Furthermore,each value as described above is allowed to vary with each base station.

When the CQI is notified with the transmission power of the RACH (FIGS.14 and 15), in the case where the mobile station cannot receive ACK fromthe base station in response to RACH transmission, or the mobile stationreceives NACK, the mobile station randomly selects a signature again,and retransmits a RACH preamble formed of the selected signature withthe same transmission power. In this case, the frequency region used inRACH transmission may be the same or different from one another.

When the CQI and RACH transmission reason is notified with thetransmission power of the RACH (FIG. 16), in the case where the mobilestation cannot receive ACK from the base station in response to RACHtransmission, or the mobile station receives NACK, the mobile stationrandomly selects one from among signatures corresponding to the RACHtransmission reason, and retransmits a RACH preamble formed of theselected signature with the same transmission power. In this case, thefrequency region used in RACH transmission may be the same or differentfrom one another.

Thus, according to the communication system according to Embodiment 2,since it is possible to implicitly notify the base station ofinformation by the transmission power of the RACH set as thetransmission control information, it is possible to increase theinformation amount notified on the random access channel. Particularly,the number of usable signatures is not significantly limited unlike theconventional way, and it is thereby possible to drastically reduce thecollision probability of the RACH.

In addition, the present invention is applicable irrespective of whetheruplink synchronization is acquired or not. Further, the subject matterof the invention is not affected even when a part of conditions differson format used in RACH transmission, coding and modulation method oftransmission data, and the other physical layers.

The present invention is not limited to the above-mentioned Embodiments,and is capable of being carried into practice with various modificationsthereof. In the above-mentioned Embodiments, sizes, shapes and the likeas shown in the accompanying drawings are not limited thereto, and arecapable of being modified as appropriate within the scope of exhibitingthe effects of the invention. Moreover, the invention is capable ofbeing carried into practice with modifications thereof as appropriatewithout departing from the scope of the object of the invention.

The invention claimed is:
 1. A mobile communication system comprising: amobile station apparatus; and a base station apparatus configured toperform communication with the mobile station apparatus, wherein themobile station apparatus sets transmission control information for usein transmission of a random access channel, the transmission controlinformation being based on each of: reception quality measured by themobile station apparatus, information classified corresponding to asituation in which the mobile station apparatus uses the random accesschannel, and broadcast information that is beforehand received from thebase station apparatus and that indicates a threshold to define acombination of the reception quality and the situation to use the randomaccess channel, and the base station apparatus performs schedulingcorresponding to a state of the mobile station apparatus, based on thetransmission control information used in transmission of the randomaccess channel from the mobile station apparatus.
 2. A mobilecommunication system, comprising: a mobile station apparatus; and a basestation apparatus configured to perform communication with the mobilestation apparatus, wherein the mobile station apparatus setstransmission control information for use in transmission of a randomaccess channel, the transmission control information being based on eachof: reception quality measured by the mobile station apparatus,information classified corresponding to a situation in which the mobilestation apparatus uses the random access channel, and broadcastinformation that is beforehand received from the base station apparatusand that indicates a threshold to define a combination of the receptionquality and the situation to use the random access channel, and the basestation apparatus performs scheduling on radio resources and amodulation scheme to allocate to the mobile station apparatus based onthe transmission control information used in transmission of the randomaccess channel from the mobile station apparatus.
 3. The mobilecommunication system according to claim 1 or 2, wherein the mobilestation apparatus uses a quality information indicator or path loss asthe reception quality, and sets, as the transmission controlinformation, one of a transmission frequency region, transmission powerand a signature of the random access channel or a combination thereof.4. A mobile station apparatus that communicates with a base stationapparatus, the mobile station apparatus comprising: a transmissioncontrol information setting device configured to set transmissioncontrol information for use in transmission of a random access channel,based on each of: reception quality measured by the mobile stationapparatus, first information classified corresponding to a situation inwhich the mobile station apparatus uses the random access channel, thefirst information being used to select, as the transmission controlinformation, one of a transmission frequency resource, transmissionpower and a signature or a combination thereof, and broadcastinformation that is beforehand received from the base station apparatusand that indicates a threshold to define a combination of the receptionquality and the situation to use the random access channel in a casewhere the mobile station apparatus performs the random access upon eachof transmission and retransmission; and a transmitting device configuredto transmit the random access channel to the base station apparatususing the transmission control information, wherein the transmissioncontrol information is implicitly informed to the base station apparatusby using a form of second information that implicitly indicates thetransmission control information.
 5. The mobile station apparatusaccording to claim 4, wherein the transmission control informationsetting device uses a quality information indicator or path loss as thereception quality, and sets, as the transmission control information,one of a transmission frequency region, transmission power and asignature of the random access channel or a combination thereof.
 6. Abase station apparatus that communicates with a mobile stationapparatus, the base station apparatus comprising: a receiving deviceconfigured to receive a random access channel from the mobile stationapparatus, the random access channel being transmitted from the mobilestation apparatus according to transmission control information set bythe mobile station apparatus, the transmission control information beingbased on each of: reception quality measured by the mobile stationapparatus, first information classified corresponding to a situation inwhich the mobile station apparatus uses the random access channel, thefirst information being used to select, as the transmission controlinformation, one of a transmission frequency resource, transmissionpower and a signature or a combination thereof, and broadcastinformation that is beforehand received from the base station apparatusand that indicates a threshold to define a combination of the receptionquality and the situation to use the random access channel in a casewhere the mobile station apparatus performs the random access upon eachof transmission and retransmission; and a scheduling device configuredto perform scheduling corresponding to a state of the mobile stationapparatus based on the transmission control information used intransmission of the random access channel, wherein the transmissioncontrol information is implicitly informed from the mobile stationapparatus by using a form of second information that implicitlyindicates the transmission control information.
 7. A base stationapparatus that communicates with a mobile station apparatus, the basestation apparatus comprising: a receiving device configured to receive arandom access channel from the mobile station apparatus, the randomaccess channel being transmitted from the mobile station apparatusaccording to transmission control information set by the mobiles mobilestation apparatus, the transmission control information being based oneach of: reception quality measured by the mobile station apparatus,first information classified corresponding to a situation in which themobile station apparatus uses the random access channel, the firstinformation being used to select, as the transmission controlinformation, one of a transmission frequency resource, transmissionpower and a signature or a combination thereof, and broadcastinformation that is beforehand received from the base station apparatusand that indicates a threshold to define a combination of the receptionquality and the situation to use the random access channel in a casewhere the mobile station apparatus performs the random access upon eachof transmission and retransmission; and a scheduling device configuredto perform scheduling on radio resources and a modulation scheme toallocate to the mobile station apparatus based on the transmissioncontrol information used in transmission of the random access channel,wherein the transmission control information is implicitly informed fromthe mobile station apparatus by using a form of second information thatimplicitly indicates the transmission control information.
 8. The basestation apparatus according to claim 6 or 7, wherein the schedulingdevice performs scheduling based on one of a transmission frequencyregion, transmission power and a signature of the random access channelof a combination thereof as the transmission control information.
 9. Amobile communication method in which a mobile station apparatus and abase station apparatus perform communication with each other, the methodcomprising: setting, using the mobile station apparatus, transmissioncontrol information for use in transmission of a random access channel,based on each of: reception quality measured by the mobile stationapparatus, information classified corresponding to a situation in whichthe mobile station apparatus uses the random access channel, andbroadcast information that is beforehand received from the base stationapparatus and that indicates a threshold to define a combination of thereception quality and the situation to use the random access channel,and using the base station apparatus to perform scheduling correspondingto a state of the mobile station apparatus, based on the transmissioncontrol information used in transmission of the random access channel.10. A mobile communication method in which a mobile station apparatusand a base station apparatus perform communication with each other, themethod comprising: setting, using the mobile station apparatus,transmission control information for use in transmission of a randomaccess channel, based on each of: reception quality measured by themobile station apparatus, information classified corresponding to asituation in which the mobile station apparatus uses the random accesschannel, and broadcast information that is beforehand received from thebase station apparatus and that indicates a threshold to define acombination of the reception quality and the situation to use the randomaccess channel, and using the base station apparatus to performscheduling on radio resources and a modulation scheme to allocate to themobile station apparatus based on the transmission control informationused in transmission of the random access channel.
 11. A method oftransmitting a random access channel from a mobile station apparatusthat communicates with a base station apparatus, the method comprising:setting transmission control information for use in transmission of arandom access channel, based on each of: reception quality measured bythe mobile station apparatus, first information classified correspondingto a situation in which the mobile station apparatus uses the randomaccess channel, the first information being used to select, as thetransmission control information, one of a transmission frequencyresource, transmission power and a signature or a combination thereof,and broadcast information that is beforehand received from the basestation apparatus and that indicates a threshold to define a combinationof the reception quality and the situation to use the random accesschannel, in a case where the mobile station apparatus performs therandom access upon each of transmission and retransmission; andtransmitting the random access channel to the base station apparatususing the transmission control information, wherein the transmissioncontrol information is implicitly informed to the base station apparatusby using a form of second information that implicitly indicates thetransmission control information.
 12. A scheduling method in a basestation apparatus that communicates with a mobile station apparatus, thescheduling method comprising: receiving a random access channel from themobile station apparatus, the random access channel being transmittedfrom the mobile station apparatus using transmission control informationset by the mobile station apparatus based on each of: reception qualitymeasured by the mobile station apparatus, first information classifiedcorresponding to a situation in which the mobile station apparatus usesthe random access channel, the first information being used to select,as the transmission control information, one of a transmission frequencyresource, transmission power and a signature or a combination thereof,and broadcast information that is beforehand received by the mobilestation apparatus from the base station apparatus and that indicates athreshold to define a combination of the reception quality and thesituation to use the random access channel, in a case where the mobilestation apparatus performs the random access upon each of transmissionand retransmission; and performing scheduling corresponding to a stateof the mobile station apparatus based on the transmission controlinformation used in transmission of the random access channel from themobile station apparatus, wherein the transmission control informationis implicitly informed from the mobile station apparatus by using a formof second information that implicitly indicates the transmission controlinformation.
 13. A scheduling method in a base station apparatus thatcommunicates with a mobile station apparatus, the scheduling methodcomprising: receiving a random access channel from the mobile stationapparatus, the random access channel being transmitted from the mobilestation apparatus using transmission control information set by themobile station apparatus based on each of: reception quality measured bythe mobile station apparatus, first information classified correspondingto a situation in which the mobile station apparatus uses the randomaccess channel, the first information being used to select, as thetransmission control information, one of a transmission frequencyresource, transmission power and a signature or a combination thereof,and broadcast information that is beforehand received by the mobilestation apparatus from the base station apparatus and that indicates athreshold to define a combination of the reception quality and thesituation to use the random access channel, in a case where the mobilestation apparatus performs the random access upon each of transmissionand retransmission; and performing scheduling on radio resources and amodulation scheme to allocate to the mobile station apparatus based onthe transmission control information used in transmission of the randomaccess channel from the mobile station apparatus, wherein thetransmission control information is implicitly informed from the mobilestation apparatus by using a form of second information that implicitlyindicates the transmission control information.
 14. A mobile stationapparatus configured to and/or programmed to communicate with a basestation apparatus, the mobile station apparatus comprising: transmittingcircuitry configured and/or programmed to: perform a random access tothe base station apparatus, the random access being performed accordingto transmission control information for transmission of a random accesschannel, and set the transmission control information based onclassified information, the classified information being based on acombination of reception quality and a situation of the mobile stationapparatus in a case where the mobile station apparatus performs therandom access upon each of transmission and retransmission, and theclassified information being used to select, as the transmission controlinformation, one of a transmission frequency resource, transmissionpower and a signature or a combination thereof, wherein the transmissioncontrol information is implicitly informed to the base station apparatusby using a form of information that implicitly indicates thetransmission control information; and receiving circuitry configuredand/or programmed to receive broadcast information including a thresholdused for classifying the reception quality.
 15. A processing methodperformed in a mobile station apparatus configured to and/or programmedto communicate with a base station apparatus, the processing methodcomprising: performing a random access to the base station apparatus,the random access being performed according to transmission controlinformation for transmission of a random access channel; setting thetransmission control information based on classified information, theclassified information being based on a combination of reception qualityand a situation of the mobile station apparatus in a case where themobile station apparatus performs the random access upon each oftransmission and retransmission, and the classified information beingused to select, as the transmission control information, one of atransmission frequency resource, transmission power and a signature or acombination thereof, wherein the transmission control information isimplicitly informed to the base station apparatus by using a form ofinformation that implicitly indicates the transmission controlinformation; and receiving broadcast information including a thresholdused for classifying the reception quality.
 16. A base station apparatusconfigured to and/or programmed to communicate with a mobile stationapparatus, the base station apparatus comprising: detecting circuitryconfigured and/or programmed to detect a random access performed by themobile station apparatus, the random access being according totransmission control information for transmission of a random accesschannel, the transmission control information being based on classifiedinformation, the classified information being based on a combination ofreception quality and a situation of the mobile station apparatus in acase where the mobile station apparatus performs the random access uponeach of transmission and retransmission, the classified informationbeing used to select, as the transmission control information, one of atransmission frequency resource, transmission power and a signature or acombination thereof, wherein the transmission control information isimplicitly informed from the mobile station apparatus by using a form ofinformation that implicitly indicates the transmission controlinformation; and transmitting circuitry configured and/or programmed totransmit broadcast information including a threshold used forclassifying the reception quality.
 17. A processing method performed ina base station apparatus configured to and/or programmed to communicatewith a mobile station apparatus, the processing method comprising:detecting a random access performed by the mobile station apparatus, therandom access being according to transmission control information fortransmission of a random access channel, the transmission controlinformation being based on classified information, the classifiedinformation being based on a combination of reception quality and asituation of the mobile station apparatus in a case where the mobilestation apparatus performs the random access upon each of transmissionand retransmission, and the classified information being used to select,as the transmission control information, one of a transmission frequencyresource, transmission power and a signature or a combination thereof,wherein the transmission control information is implicitly informed fromthe mobile station apparatus by using a form of information thatimplicitly indicates the transmission control information; andtransmitting broadcast information including a threshold used forclassifying the reception quality.